I used a signal follower listening to an input from es-8 module receiving a slow Doepfer A-145 triangle LFO. The Renoise env follower gets routed to a midi control device mapped to the cutoff of my vst synth. From there I have the track with the VST sending out another of the es-8 outputs and further process the signal to record back into Renoise. Playing around with the sensitivity of the signal follower allows you to change how much that lfo impacts the assigned value.